Two years ago, a 12-year-old German boy became perhaps the youngest-ever patient to embark upon a sex change.
Since then, the child, known only as Kim -- and formerly known as Tim -- has begun a course of hormone treatments designed to stop puberty in its tracks, preventing facial hair growth and other secondary sex characteristics experienced by boys of that age.
The hormone treatment will also give Kim breasts. And once Kim turns 18, Kim will likely have the surgery that will complete Kim's transformation into a young woman.
The treatments have sparked debate among many who worry that Kim may be too young to fully understand the ramifications of this unusual decision.
However, Dr. Achim Wüsthof, the pediatric endocrinologist who oversees Kim's treatment, says the child's case was very clear-cut from a young age, suggesting that Kim had been a little girl trapped in a little boy's body for as long as she could remember.
"She started when she was 3 or 4 thinking that she was a girl," says Wüsthof, who is affiliated with the Endokrinologikum Center in Hamburg.
"It was always very clear that from her point of view she was a girl. So when she turned 12 and puberty started, there was some anxiety and panic at the prospect of the male puberty process continuing. That was the moment that the family came to see me."
But not all experts in the field agree that beginning the transition from male to female is appropriate at such an early age.
"Frankly, I find this troubling news," says Dr. Neera Ghaziuddin, associate professor of psychiatry at the University of Michigan. Ghaziuddin works with preteens and teens with psychological problems, and she says that although she is not intimately familiar with all the details of Kim's case, the fact that the treatment has started causes her concern.
"Most 12-year-olds are still struggling with many aspects of their identity, so a permanent or a semi-permanent procedure to change gender would be undesirable, in my opinion," Ghaziuddin says.
Kim's therapy, which entails using potent hormones to arrest the changes associated with male puberty, is reversible -- for now.
"The breast development, after a certain point, will not be completely reversible unless there is an operation," Wüsthof says. "But if we stop now, within a few months Kim will be a young man."
Regardless, Wüsthof says the decision to allow Kim to go forward with the treatment was not made lightly. In accordance with German law, two independent psychiatrists were consulted on the case -- and they considered Kim's situation so profound that both recommended that treatment should proceed.
Psychological experts say that Kim's conviction could be seen as confirmation that going forward with the treatment was the proper course of action in this case.
"Two things would need to be seen here: longevity of female identification -- in other words, the individual in question should have identified as a girl since age 5 or 6 without ambiguity -- and no other signs of psychological disturbance," says Jay Reeve, assistant professor at Florida State University's department of psychology.
"It sounds as if both conditions were met in this case."
"If the kid is starting from very early in saying that he or she feels like a boy or a girl, then that's a very decisive moment," Wüsthof says. "Then it becomes very convincing that they do not belong to their biological sex."
The intervention may have also come at a critical time for the child. In most cases, hormone therapy in preparation for sexual reassignment surgery occurs at a much later age. However, there were concerns that the lower voice and facial hair growth that come along with male puberty could have been traumatic for Kim.
"If the family is noticing some extensive concern on the child's part with experiencing secondary sex characteristics, such as a deepening voice and facial hair, then that is a strong sign as well," says Michele Angello, a clinical psychologist who works with adolescents who also experience transgender tendencies.
"It becomes a problem when they are close to puberty and they begin to exhibit anxiety, depression or suicidal ideations."
Along with igniting a debate over the propriety of beginning the path toward sexual reassignment in such a young patient, Kim's case has also fed the discussion over whether gender preferences are in the mind or in the hormones.
"That's the $64,000 question," Reeve says, adding that recent studies have suggested that biology or genes might play an important role.
"But I'm unaware of any discovery of a clear-cut, uncontested genetic marker, such as an anomaly in brain development, that would account for this," Reeve says. "In other words, there are probably some environmental factors, but it's impossible to say without more information."
It is also likely that on some level, psychology plays an important role.
"The complicated but simple answer is that it is probably an interplay between the two, though certainly the impetus is probably something endocrine," Angello says.
But one thing is certain with regard to the therapy -- medical ethicists and the public will continue to debate whether such treatments should be allowed for young patients.
"I think that there will continue to be a great deal of controversy around this sort of procedure, regardless of the outcome here, for some time to come," Reeve says. "This is just because of the uncertainty within the field regarding the true roots of gender identity."